Friday, April 18, 2014

Declining Central American Green Turtles

A 20-year assessment of Nicaragua's legal, artisanal green sea turtle fishery has uncovered a stark reality: greatly reduced overall catch rates of turtles in what may have become an unsustainable take, according to conservation scientists from the Wildlife Conservation Society and University of Florida.

During the research period, conservation scientists estimated that more than 170,000 green turtles were killed between 1991 and 2011, with catch rates peaking in 1997 and 2002 and declining steeply after 2008, likely resulting from over-fishing. The trend in catch rates, the authors of the assessment results maintain, indicates the need for take limits on this legal fishery.

The study now appears in the online journal PLOS ONE. The authors are: Cynthia J. Lagueux and Cathi L. Campbell of the University of Florida (formerly of the Wildlife Conservation Society), and Samantha Strindberg of the Wildlife Conservation Society.

"The significant decrease in the catch rates of green turtles represents a concern for both conservationists and local, coastal communities who depend on this resource," said Dr. Lagueux, lead author of the study. "We hope this study serves as a foundation for implementing scientifically based limits on future green turtle take."

Caribbean coastal waters of Nicaragua contain extensive areas of sea grass, principal food source for green turtles, the only herbivorous sea turtle species. Green turtles in turn support a number of indigenous Miskitu and Afro-descendant communities that rely on the marine reptiles for income (by selling the meat) and as a source of protein.

The catch data used by the researchers to estimate trends was gathered by community members at 14 different sites located in two geographically political regions of the Nicaraguan coast. The research team analyzed the long-term data set to examine catch rates for the entire fishery, each region, and for individual turtle fishing communities using temporal trend models.

Over the duration of the assessment, the scientists recorded that at least 155,762 green turtles were caught; the overall estimated catch (factoring in estimated take during periods when data were not recorded) was 171,556 turtles. The average catch rate per fishing trip (assuming average fishing effort in terms of nets used and trip length) revealed an overall decline from 6.5 turtles to 2.8 turtles caught, representing a 56 percent decline over two decades.

In individual communities, catch rate declines ranged between 21 percent and 90 percent in green turtles caught over the 20-year period.

"These declining catch rates align with our survival rate estimates of green turtles exposed to the Nicaragua turtle fishery and population modelling, which suggested the fishery was not sustainable at high take levels reported in the 1990s," said Dr. Cathi Campbell.

The steep declines in green turtle catch rates, the researchers maintain, indicate a potential decline of green turtle populations that use Nicaragua's foraging grounds, particularly smaller rookeries in the Caribbean. The scientists note that the study results highlight the need for not only close monitoring of rookeries in the region, but also in-water aggregations of green turtles. Further, future research efforts should include the use of molecular technology to better refine Caribbean green turtle genetic stocks, specifically to identify populations most at risk from turtle fisheries.

"Given the importance of green turtles to Nicaragua's past, present and future, we encourage the communities, governmental agencies, and conservation groups to take measures that conserve and sustain these globally threatened populations, and to work together to ensure that the communities have alternative sources of protein and income into the future," said Dr. Caleb McClennen, Director of WCS's Marine Program.

Growing up to 400 pounds in weight, the green turtle is the second largest sea turtle species next to the leatherback turtle. The reptile inhabits the tropical and subtropical waters of the world. The species is listed as Endangered on the IUCN's Red List and on CITES (Convention on International Trade in Endangered Species of Wild Flora and Fauna) as an Appendix I species, a designation which prohibits all international commercial trade by member countries. In addition to the threat from overfishing (intentional take), the green turtle is at risk from bycatch in various fisheries (unintended take), poaching of eggs at nesting beaches, habitat deterioration and loss due to coastal development and climate change effects, and pollution.

Citation
Cynthia J. Lagueux, Cathi L. Campbell, Samantha Strindberg. Artisanal Green Turtle, Chelonia mydas, Fishery of Caribbean Nicaragua: I. Catch Rates and Trends, 1991–2011. PLoS ONE, 2014; 9 (4): e94667 DOI: 10.1371/journal.pone.0094667

Wednesday, April 16, 2014

On the importance of natural history

Support in developed countries for natural history -- the study of the fundamental nature of organisms and how and where they live and interact with their environment -- appears to be in steep decline. Yet natural history provides essential knowledge for fields as varied as human health, food security, conservation, land management, and recreation. In the April issue of BioScience, a group of scientists from institutions across North America details examples supporting their conviction that a revitalization of the practice of natural history will provide important benefits for science and society.

The 17-member group of authors, convened by Joshua J. Tewksbury of the University of Washington and the World Wide Fund for Nature's International office, notes that 75 percent of emerging infectious diseases of humans, including avian influenza, Lyme disease, cholera, and rabies, are linked to other animals at some point in their life cycle. Control strategies rely on knowledge of these hosts' natural history.

Sustainable agricultural practices, such as companion planting, crop rotation, and pest control, likewise rely on knowledge of natural history, much of which was, however, discarded with the Green Revolution. Effective fisheries management relies on natural history -- disasters such as the collapse of the Bering Sea walleye pollock fishery might have been avoided had it been used sooner. Rigorous forest fire suppression in the western United States during much of the twentieth century was another costly mistake that might have ended sooner if natural history knowledge had been used earlier. And recreational hunting and fishing have often benefited when interest groups applied knowledge of natural history and suffered when it was ignored.
Despite this, natural history collections are not expanding, and the number of active herbaria has declined since 1990 in Europe and North America. The majority of US schools now have no natural history requirements for a biology degree, a trend that has coincided with the rise of molecular, experimental, theoretical, and other forms of biology. These types of biology may be less expensive or be more likely to attract large grants and public recognition. The stagnation could also reflect more general public disengagement with nature in developed countries.

Although biological modeling has become more sophisticated, Tewksbury and his coauthors note that models must be built on field observations to usefully represent the real world. The important influence of microbes on human health and plants is a key new frontier in natural history research, the authors believe. And they see hope for the discipline, both within and outside of traditional natural history collections, in the rise of Internet- and smart phone-based technologies that allow the growth of broad partnerships, including citizen-science initiatives. Such linkages are starting to develop, but will need established professionals to self-identify as natural historians to provide the leadership needed for natural history to reclaim its necessary role, the authors assert

Citation
J. j. Tewksbury, J. G. T. Anderson, J. D. Bakker, T. J. Billo, P. W. Dunwiddie, M. J. Groom, S. E. Hampton, S. G. Herman, D. J. Levey, N. J. Machnicki, C. M. del Rio, M. E. Power, K. Rowell, A. K. Salomon, L. Stacey, S. C. Trombulak, T. A. Wheeler. Natural History's Place in Science and Society. BioScience, 2014; DOI: 10.1093/biosci/biu032.

Suizo Report -- Plot Biscuits

Howdy Herpers,                                     04/14/14

We trust that your inbox has been devoid of Suizo Reports lately? The president of the THS can’t imagine what he has been doing with all of his free time………..

We should take a moment to explain the numbers that appear in parenthesis after the snake numbers for any of the people on this list who don’t live, breathe, and die herps. No, we don’t have 3.6 Tiger Rattlesnakes---although tracking 6 tenths of a tiger might be as exciting as tracking a whole one. No, the first number is always a male--until somebody changes that. Just as sure as shootin, some idiot is going to come along and mess with that someday soon. But for now, the numerical logic stands thusly. Males first! (Dammit).  

By early March, all 2.4 of the molossus were jacked up and on the move. At the date of this writing, only two tigers, 1.1, have made any movements to speak of. But those 2 are off and running now.

We’ve already had two major feeding events. On 29 March, Marty and I tracked our big male molossus CM12 “Jerry” to a hackberry thicket in Suizo Wash. (That’s right, he is already off Iron Mine Hill and heading for his summer range--which goes as far as 2 miles west of his overwintering site). As pictures 1 and 2 clearly demonstrate, he has choked down something big. Our first guess is a rock squirrel, but it could also be a big packrat. Picture 3 shows him, still at the same location, on 12 April. That is by far the oddest basking posture I’ve seen to date with any species of rattlesnake.






Also on 29 March, our sweet young female tiger CT13, “Katey” was carrying an enormous food bolus. Were I to venture a guess, it would be a large adult K-rat. In any case, I’m sure that most would agree the bolus is mammalian in shape. Picture #4 in this report is the first in a series of the digestive process, and was taken on 29 March. Picture #5 was taken on 5 April, and picture #6 on 12 April. Note that the bolus has shifted toward her cloaca in this last image of her.




There is much more to report, but in the spirit of getting this sent off today, we stop here.  

This here is Roger Repp, signing off from paradise, where the turtles are strong, the snakes are handsome, and the lizards are all above average. I hope to see a bunch of you tomorrow night!

We currently have 16 rattlesnakes carrying transmitters. One of these is a young male Western-Diamond-backed Rattlesnake (Crotalus atrox). This snake has been a crashing bore, a veritable dud-in-the-mud. Watching wet paint dry would be more exciting. Hence, we are done talking about his sorryass. We have a total of six (2.4) Black-tailed Rattlesnakes (Crotalus molossus), and nine (3.6) Tiger Rattlesnakes (Crotalus tigris).

Monday, April 14, 2014

Saint-Girons' Sea Krait uses nurseries

Sea kraits (Laticauda) are amphibious snakes widely distributed in the coral reefs of the East Indian and West Pacific Ocean. They forage in the ocean but return to land, usually coralline islets, for resting, shedding skin, an
d digesting prey. Their dependence on coastal terrestrial habitats puts them at risk because of  increasing human populations and rapid industrial and mining developments that threaten coastlines. Human activities also contaminate the prey consumed by sea snakes. Many populations of sea kraits collapsed during the last three decades, due to habitat loss and massive harvesting for the leather industry.

Sea kraits are oviparous, and they lay their eggs on land. Communal nesting in tidal caves has been observed in two species (L. semifasciata and L. schistorhyncha) in Philippines, Taiwan and Niue islands. This information is anecdotal and the oviposition sites remain unknown for the six other species of  Laticauda. Additionally there are no data concerning the ecology of neonates or juveniles.

In a new study Bonnet and colleagues provide the first ecological data available on juveniles and coastal nurseries and propose simple practical conservation actions.

The study revealed that in New Caledonia, the maintenance of most yellow sea krait populations depends on few coastal nurseries. The populations contains a very small number of neonates or juveniles, thus local recruitment is extremely low. Careful long-term surveys of tens of islets in the southwestern-lagoon enabled us to find only two important and highly localized nurseries, respectively situated on two islands separated by 161 km: Verte Islet in the North and Ouen Island in the South. Ouen Island was remarkable, however, for two reasons: first the very high number of neonates and juveniles associated with very small number of adults was very unusual; second, this island is surrounded by many very different colonies. Ouen Island is indeed situated in a very large part of the lagoon; the barrier reef is more than 60 km offshore. This region of the lagoon contains many islets, essentially or exclusively populated by adults, spread from the line-coast to the barrier reef. This pattern suggests that likely hundreds of females converge every year to Ouen Island to lay their eggs.

Sea kraits are characterized by a low fecundity. In L. saintgironsi, the mean clutch size is 3.3 and females breed every two years on average. Considering the crude neonate number we estimated (~1,700), more than 500 females laid their eggs in the nursery during the winter 2010. There is no colony that shelters such a corresponding high number of reproductive females. Adult sea kraits display a very high fidelity to their colony, but very few adult females have been observed in Ouen Island. Thus, most of the females traveled from distant sites (sometimes more than 50 km) toward Ouen Island, and later returned home after having laid their three eggs. Ouen Island and possibly other similar nursery locations (yet undiscovered) likely supply a large proportion of juveniles for most populations of yellow sea kraits.

The authors did not find the nests (probably deeply hidden into crevices) and hence could not measure the specific environmental conditions in the laying sites, peculiar environmental conditions that prevail in coastal versus offshore sites might explain why many gravid females converged to the nurseries. In oviparous reptiles, incubation requires well-buffered thermal and hydric conditions. Ouen Island is a large basaltic island, physically extremely different from the flat sandy coralline islets that shelter most colonies. Coastal sites catch greater amount of rain and ambient temperature is more stable compared to remote islets. Thus, rocky coastal shores may provide thermally buffered and relatively humid microhabitats that are suitable for incubation. Interestingly, in the Ouen Island nursery, during the egg-laying period in late November, the authors found seven adult sea kraits sheltered in crevices under large rocks situated 50 m inshore, six were females and five were gravid. In strong contrast, in offshore sandy islets, large protective rocky structures and neonates are absent.

The Ouen Island nursery plays another essential role. The clearly multimodal distribution of body sizes shifted over seasons and  recapture data suggests the existence of successive cohorts of young snakes. Many juveniles belonging to each cohort remained in the nursery over prolonged periods (several months). During this time they do feed and grow. This suggests that many juveniles utilize the nursery before dispersal across the lagoon. Although mortality accounted for an unknown proportion of the progressive decrease in the size of each cohort, dispersal was important in this process as revealed by the very low local recruitment rate and the very small number of adults. Ouen Island nursery functions as dispersal springboard for juveniles. In 2012, we recaptured an adult yellow sea krait marked as a neonate in Ouen Island in 2010 on an islet situated 18 km away.  This information is anecdotal, but this nonetheless demonstrates the great dispersal ability of very small sea kraits, and the fast growth rate of juveniles.

Protecting nurseries should be a conservation priority to protect laying females, nesting sites, neonates, and  juveniles during a prolonged pre-dispersal phase. In addition, building artificial laying sites in coralline islets may represent an option to promote recruitment in threatened populations; such constructions also offer appropriate shelters to adult snakes.

Citation
Bonnet X, Brischoux F, Bonnet C, Plichon P, Fauvel T (2014) Coastal Nurseries and Their Importance for Conservation of Sea Kraits. PLoS ONE 9(3): e90246. doi:10.1371/journal.pone.0090246

Climate change impacts reptiles and birds in the southwest


Arizona Black Rattlesnake, Crotalus cerberus
Awareness and acceptance of climate change is slowly spreading  in American society. In a report released by the USGS' Department of the Interior reports the results of modeling current and  future breeding ranges of seven bird and five reptile species in the Southwestern United States with sets of landscape, biotic (plant), and climatic global circulation model (GCM) variables. Charles van Ripper and colleagues (2014) considered climatic, landscape, and plant variables to developing and testing probabilistic models. Climatic variables included the maximum and minimum mean monthly and seasonal temperature as well as precipitation for three time periods. Landscape features included terrain ruggedness and insolation. They also considered plant species distributions as candidate explanatory variables where prior ecological knowledge implicated a strong association between a plant and animal species.

Projected changes in range varied widely among species, from major losses to major gains. Breeding bird ranges exhibited greater expansions and contractions than did reptile species. The authors projected range losses for Williamson’s sapsucker and pygmy nuthatch of a magnitude that could move these two species close to extinction within the next century. Although both species currently have a relatively limited distribution, they can be locally common, and neither are presently considered candidates for prospective endangerment. Breeding bird ranges exhibited greater expansions and contractions than did reptile species.

The authors also project range losses of over 40 percent, from its current extent of occurrence, for the plateau striped whiptail, Arizona black rattlesnake, and common lesser earless lizard. Currently, these reptile species are thought to be common or at least locally abundant throughout their ranges.  The total contribution of plants in each distribution model was very small, but models that contained at least one plant always outperformed models with only physical variables (climatic or landscape). The magnitude of change in projected range increased further into the future, especially when a plant was in the model.

Bird species with the strongest association to a landscape feature during the breeding season, such as terrain ruggedness and insolation, exhibited the smallest contractions in projected breeding range in the future. In contrast, bird species that had weak associations with landscape features, but strong climatic associations, suffered the greatest breeding range contractions. Thus, landscape effects appeared to buffer some of the negative effects of climate change for some species.

The magnitude of change in projected bird  breeding range was positively related to the annual average temperature of their baseline distribution, thus species with the warmest breeding ranges exhibited the greatest changes in future breeding ranges. This pattern was not evident for reptiles, but might exist if additional species were included in the model.

The results provide managers with a series of projected range maps that will enable scientists, concerned citizens, and wildlife managers to identify what the potential effects of climate change will be on bird and reptile distributions in the Western United States. The authors  hope that the results can be used in proactive ways to mitigate some of the potential effects of climate change on selected species.

The entire document is available on-line.

Citation
Charles van Riper III, James R. Hatten, J. Tom Giermakowski, David Mattson, Jennifer A. Holmes, Matthew J. Johnson, Erika M. Nowak, Kirsten Ironside, Michael Peters, Paul Heinrich, K. L. Cole, C. Truettner, and Cecil R. Schwalbe 2014. Projecting Climate Effects on Birds and Reptiles of the Southwestern United States. Open-File Report 2014-1050, U.S. Department of the Interior, U.S. Geological Survey. 100 pp

Thursday, April 10, 2014

The monotypic Alligator Snapping Turtle is now three species

The Alligator Snapping Turtle, Macrochelys temminckii, has gone from being a monotypic species of southeastern North American rivers and the main ingredient in turtle soup to an endangered species that is now three distinct species. This transformation took less than 50 years. Thomas et al. (2014) note previous molecular analyses using mitochondrial and nuclear DNA suggested Macrochelys exhibited significant genetic variation across its range and includes three distinct genetic assemblages (western, central, and eastern = Suwannee).

However, no taxonomic revision or morphological analyses have been conducted previously. Thomas et al.  tested previous hypotheses of geographic assemblages by examining morphology, reanalyzing phylogeographic genetic structure, and estimating divergence dating among lineages. They reviewed the fossil record and discuss phylogeographic and taxonomic implications of the existence of three distinct evolutionary lineages. They found morphological and molecular data suggest significant geographical variation and suggest three species-level breaks among genetic lineages that correspond to previously hypothesized genetic assemblages. The holotype of Macrochelys temminckii is from the western lineage. They describe two new species: Macrochelys apalachicolae sp. nov. from the central lineage and Macrochelys suwanniensis sp. nov. from the eastern lineage (Suwannee River drainage). Their estimates of divergence times suggest that the most recent common ancestor (MRCA) of M. temminckii (western) and M. apalachicolae (central) existed 3.2–8.9 Ma during the late Miocene to late Pliocene, whereas M. temminckii-M. apalachicolae and M. suwanniensis last shared a MRCA 5.5–13.4 Ma during the mid-Miocene to early Pliocene. Examination of fossil material revealed that the fossil taxon Macrochelys floridana is actually a large Chelydra. 

Citation

Thomas, TM, Granatosky, MC, Bourque JR, Krysko, KL, Moler, PE, Gambel, T, Suarez, E., Enge, KM, and Roman, J. 2014.  Taxonomic assessment of Alligator Snapping Turtles (Chelydridae: Macrochelys), with the description of two new species from the southeastern United States. Zootaxa 3786 (2): 141–165  

Saturday, April 5, 2014

The Indigo Snake and the Mine

The Eastern Indigo Snake. Photo credit: US Fish & Wildlife Service
By David Fleshler, Sun Sentinel
April 6, 2014

The expansion of a rock mine in southwestern Palm Beach County could kill up to a dozen federally protected eastern indigo snakes, the longest native snake in North America, according to a wildlife agency report.

The Star Ranch is seeking permission from the Army Corps of Engineers to expand its limestone mine by 1.4 square miles to produce construction materials for roads, Everglades restoration and other projects. The U.S. Fish and Wildlife Service says the work could "crush indigo snakes, their nests and eggs," killing up to 12 of the 23 that may live there.

None of the snakes, which can reach a length of up to eight and a half feet, have been seen on the property, the wildlife service said. But the service said the site is the type of land they use, they have been seen around it and they're difficult to find because they live primarily underground.

Noel Shapiro, a sugar cane farmer who owns the property, could not be reached for comment, despite a phone call to his office. Broward contractor Ron Bergeron, whose company has long had an agreement to mine the land, said he hadn't seen the report. He noted the service admits not finding any snakes on the site.

"They're just making an assumption that there's 23, but nobody's seen one," said Bergeron, who is one of seven volunteer commissioners who run the Florida Fish and Wildlife Conservation Commission.
Bergeron said 90 percent of the mine's materials will go toward public road-building and Everglades restoration projects - the reservoirs, levees and other structures that will conserve and clean water for the Everglades. Without a nearby mine, he said, the rock would have to be brought at much higher cost from western Miami-Dade County.

Indigo snakes, which have the rich black color of a grand piano, live in parts of Georgia and Florida, mostly from Central Florida down through the Keys. Non-venomous – and popular for that reason for wildlife shows – the snakes eat fish, snakes, frogs, young gopher tortoises, small mammals and small alligators.

Protected as threatened under the Endangered Species Act, the snakes have declined mainly from loss of habitat to development, according to the Fish and Wildlife Service. Other causes include capture for the pet trade and rattlesnake roundups, in which participants spray gasoline into gopher tortoise burrows, where indigo snakes and other animals live, to flush out rattlesnakes.

Environmentalists have long opposed the expansion of mining in western Palm Beach County, saying it ruins the landscape and leaves behind deep holes that drain water that should flow through the Everglades.

Drew Martin, conservation chair of the Sierra Club Loxahatchee Group, said other projects, such as the proposed development of the Briger tract in northern Palm Beach County, would kill indigo snakes.

"We have the snakes being threatened in a lot of places," he said. "The more we reduce the number of indigo snakes, the more we run the risk that the snake could become extinct."

The opinion letter from the U.S. Fish and Wildlife Service does not say the work should not go forward. Although it said the work would "adversely affect" the species, the letter said the mine would not "jeopardize" its existence, the trigger that could hold up a project. The letter said the mining work would have to comply with standard procedures published by the

Tuesday, April 1, 2014

Boa & Python Specialist Group report on captive breeding


31 March 2014 | International news release
Indonesia, Malaysia and Viet Nam are the main source of 
python skins, with China, Thailand and Viet Nam all 
producing python skins through farming. Photo credit: 
Daniel Natusch / IUCN

The first report under the ‘Python Conservation Partnership’, a collaboration between Kering, the International Trade Centre (ITC) and the Boa and Python Specialist Group of the International Union for Conservation of Nature, has been presented today.

The “Assessment of Python Breeding Farms Supplying the International High-end Leather Industry” is a study evaluating the economic feasibility and viability of captive breeding of pythons as a possible element of sustainable use and conservation of the species. Its aim is to provide guidance to those involved in the python trade to adopt sustainable practices when sourcing skins.

According to the report, python farming could help reduce pressure on wild python populations in Asia. The practice, however, should be viewed only as part of a holistic approach to python conservation and additional research on python farming and trade is required to determine its conservation benefits and impacts on livelihoods. The report also found that greater emphasis on the conservation of python species in the wild is needed.

“It is encouraging to finally have some concrete information about the feasibility and role of farming pythons for skins, particularly given the previous concerns raised about whether it was possible or not,” said Daniel Natusch, one of the authors of the report and member of the IUCN SSC Boa and Python Specialist Group. “Captive breeding is only part of a possible solution for a sustainable python skin trade. We shouldn't lose sight of overall conservation goals and the greater potential of wild harvest systems to encourage conservation of wild pythons and their habitats.”

Key recommendations from the report include putting in place systems to ensure that python farming is well documented and that any trade is sustainable, legal and does not encourage trafficking from the wild under the guise of farmed animals. The study also highlights the urgent need to develop techniques to differentiate between captive-bred and wild-caught skins. The Python Conservation Partnership is currently addressing this issue by working with Viet Nam to research innovative ways to determine whether skins are derived from captive-bred or wild sources.

“Our drive and commitment to sustainable business includes going deep into sustainability across our supply chains, right to our sources,” said Marie-Claire Daveu, Chief Sustainability Officer and Head of international institutional affairs of Kering. “This first report and the continued work we are doing in the Python Conservation Partnership to enhance traceable, sustainable sourcing and the conservation of pythons will assist our sector and move the industry towards more informed decisions in python sourcing. We will be proactive in addressing these recommendations, and in particular developing best practice guidelines in the PCP for captive breeding farms and training the suppliers we work with."

Python skins are traded primarily to meet demands from the fashion industry to make luxury leather products, with Italy, Germany and France being the biggest importers. Skins are also used for traditional Chinese musical instruments. Indonesia, Malaysia and Viet Nam are the main source of python skins, with China, Thailand and Viet Nam all producing python skins through farming.

Southeast Asia’s pythons, the Reticulated Python (Python reticulatus) and the Burmese Python (Python molurus bivittatus) - which are two of the world’s largest snakes - have been harvested from the wild for their skins for almost eight decades. Within the last 20 years, the scale of trade in python skins has increased significantly with nearly 500,000 skins exported from Southeast Asian countries per year. Continued increase in demand is likely to put significant pressure on wild stocks, according to the study.

“This report offers a possible alternative solution to the sourcing of python skins for which demand is escalating. However, there is still some way to go towards more transparent, better managed python farming,” said Jean-Christophe ViĆ©, Deputy Director of IUCN’s Global Species Programme. “We must make sure that attention is not diverted from the urgent need to preserve wild pythons and their habitats through direct site conservation and action against illegal trade.”

The report will be presented at the Animals Committee of the upcoming Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) meeting in May 2014 to contribute to the discussion on international snake trade.

"CITES is seeking to improve the legality, sustainability and traceability of international trade in pythons. It has called for further research to help the CITES Animals and Standing Committees determine what guidance should be provided and additional steps taken to ensure the ongoing sustainability and legality of this trade,” said John E. Scanlon, Secretary-General Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES). “This effort is bringing the relevant players together across all sectors to find pragmatic and innovative solutions. The “Assessment of Python Breeding Farms Supplying the High-end Leather Industry”, delivered under the Python Conservation Partnership, is making a highly valuable contribution towards this collective undertaking.”

Thursday, March 27, 2014

Dehydration in sea snakes

Like camels of the sea, a species of sea snake goes without a drink for months on end, gradually dehydrating, before refueling with freshwater when rain falls, new research suggests.

"Perhaps six or seven months of the year, these snakes are living thirsty," said Coleman Sheehy III, an evolutionary biologist at the University of Florida, and a co-author of the study published March 18 in the journal Proceedings of the Royal Society B.

Past studies have found that snakes can dehydrate for short periods of time and then gulp freshwater when it's available, but those snakes typically have access to freshwater sources such as nearby springs. [Image Gallery: Snakes of the World]

The yellow-bellied sea snake, Hydrophis platurus, by contrast, has a vast range and habitat. The 3.3-foot-long snakes drift along ocean currents feeding on fish, and are found in the middle of the vast Indian and Pacific oceans, spending months without any freshwater sources.

To understand exactly how they manage this feat, Sheehy and his colleagues gingerly collected hundreds of the wild sea snakes in the Guanacaste province of Costa Rica. (The sea snakes have a nasty, venomous bite, though no one has died from one, Sheehy said.) In that region, the dry season lasts from December to May or June, and the snakes were collected on several different trips at different points in both seasons.

'They tank up during the rainy season and then it takes a while for them to get thirsty enough to drink.'
 Coleman Sheehy III, an evolutionary biologist at the University of Florida

They then took the snakes back to their lab, towel-dried them, and measured and weighed them.

Next, they placed the snakes in freshwater tanks to see whether the sea creatures drank.

Snakes collected after long dry spells were extremely skinny, because they had been slowly drying out. The slimmest snakes also drank freshwater in the lab aquariums, plumping up and rehydrating.

But many snakes collected during the rainy season and shortly afterward didn't sip a drop of water, suggesting they can go quite a while, even one to two months, before they get the urge to rehydrate.

"They tank up during the rainy season and then it takes a while for them to get thirsty enough to drink," Sheehy told Live Science.

The team suspects that H. platurus has evolved adaptations to prevent freshwater loss through the skin.

But at some point, the sea snakes need to drink, so where do they get their water?

"The only source of freshwater for a marine snake like this species that's living in the middle of the ocean is rainfall," Sheehy said.

During rainy periods, the rainfall floats at the top of the denser saltwater ocean and accumulates in layers known as freshwater lenses. It's these freshwater lenses that provide a drink for the parched yellow-bellied sea snake.

The snakes are hardwired to come up to the surface to drink, even when they are in a freshwater aquarium where a good drinking source is all around them, Sheehy said.

The new study shows that animals that evolved on land but then moved into the seas have developed a unique array of adaptations to their salty home. For instance, whales seals, sea turtles and other animals have evolved not to need any freshwater access at all either by having salt glands that process seawater, or by extracting water from their food, Sheehy said.

"Instead of adapting to marine environments like many other vertebrates have, these animals, sea snakes, have taken a different approach," Sheehy said.

Citation
HB Lillywhite, CM. Sheehy III, F Brischoux, and A Grech. 2014. Pelagic sea snakes dehydrate at sea. Proceedings of the Royal Society B.May 7, 2014 281 1782 20140119; doi:10.1098/rspb.2014.0119 1471-2954

Sunday, March 23, 2014

Homing & navigation in the invasive Python bivittatus

Evidence for homing behavior and navigation in snakes has been around for awhile see Stickel and Cope (1947) and such behavior should not be at all surprising in Python bivittatus, so keep this in mind while reading the popular press release below.

By Mickie Andersson, University of Florida News Center

GAINESVILLE — If you pick them up and drop them in a new location, most snakes will move rapidly but erratically, often traversing the same terrain before giving up and settling into their new digs.

A team of researchers including scientists from the University of Florida has discovered that the giant snakes — which have invaded and affected the food chain in Everglades National Park and Big Cypress National Preserve — can find their way home even when moved more than 20 miles.

The findings, published last week by the Royal Society’s Biology Letters, change how researchers understand pythons’ behaviors and intellect.

“This is way more sophisticated behavior than we’ve been attributing to them,” said Frank Mazzotti, a UF wildlife ecology and conservation professor based at the Fort Lauderdale Research and Education Center. “It’s one of those things where nature makes us go ‘wow.’ That is truly the significance of this.”

In 2006 and 2007, researchers captured 12 pythons and surgically implanted radio transmitters that allowed them to track the snakes’ movements. As a control group, they returned six of the snakes to the spot of their capture and turned them loose.

The remaining six snakes were taken to spots ranging from 13 to 22 miles away from where they had been captured and turned loose. To the researchers’ surprise, the snakes oriented themselves toward “home” and maintained their bearings as they traveled.

And although it took between 94 and 296 days for five of the six snakes to get within three miles of home, partly due to it being the snakes’ dormant season, the reptiles kept that orientation — a clear signal to scientists that the snakes have both “map” and “compass” senses.

The relocated snakes appeared to use local cues at the release site to understand their position relative to home (the map sense), and appeared to use cues along the way (their compass sense) to ensure that they remained on track, although the researchers don’t yet know what those cues are: smell, perhaps the stars, light or some kind of magnetic force.

Mazzotti said it’s helpful for researchers to know that the snakes move purposefully through their environment, but in reality, it’s not that much help.

“It amps up a little bit our concern about the snakes, but given all the other things we know about pythons, the amount of increasing concern is minor,” he said.

The Burmese python has been an invasive species in South Florida since about 2000, likely stemming from accidental or purposeful releases by former pet owners. The largest python found in the Everglades area had grown to more than 18 feet.

The snakes suffocate and eat even large animals, such as deer and alligators, and in 2012, a research team that included Mazzotti found severe declines in sightings in python-heavy areas of native animals including raccoons, opossum, bobcats and rabbits.

In 2012, the federal government banned the import and interstate trade of four exotic snake species: the Burmese python, the yellow anaconda, and North and South African python.

Citations
Pittman SE, Hart KM, Cherkiss MS, Snow RW, Fujisaki I, Smith BJ, Mazzotti FJ, and Dorcas ME. 2014. Homing of invasive Burmese pythons in South Florida: evidence for map and compass senses in snakes Biol. Lett. March, 2014 10 3 20140040; doi:10.1098/rsbl.2014.0040 1744-957X.

Stickel, WH. Cope JB. 1947. The home ranges and wanderings of snakes. Copeia, 127-136.

Thursday, March 20, 2014

Rukwanyoka holmani; the oldest advanced venomous snake

A vertebrae of the oldest fossil venomous snake 
Rukwanyoka holmani in Africa. Photo Credit:
Ohio University.
Ohio University scientists have found the oldest definitive fossil evidence of modern, venomous snakes in Africa, according to a new study published March 19 in the journal PLOS ONE.

The newly discovered fossils demonstrate that elapid snakes—such as cobras, kraits and sea snakes—were present in Africa as early as 25 million years ago, said lead author Jacob McCartney, a postdoctoral researcher in the Ohio University Heritage College of Osteopathic Medicine. He's part of a team that has been examining the Rukwa Rift Basin of Tanzania over the last decade to understand environmental change through time in the East African Rift System.

Elapids belong to a larger group of snakes known as colubroids, active foragers that use a variety of methods, including venom, to capture and kill prey.

Colubroid fossils are documented as early as 50 million years ago. But they weren't expected to constitute such a large part of the African snake fauna 25 million years ago, as they became dominant in Europe and North America much later.

"In the Oligocene epoch, from about 34 to 23 million years ago, we would have expected to see a fauna dominated by booid snakes, such as boas and pythons. These are generally 'sit and wait' constricting predators that hide and ambush passing prey," McCartney said.

In fact, the recent study includes a description of the oldest evidence of African booid snakes, he said. The researchers have named this new species Rukwanyoka holmani; the genus name combines the Rukwa region name with the Swahili word for snake, and the species name is in honor of J. Alan Holman, a paleontologist and mentor.

However, the team was surprised to discover that the fauna actually revealed more colubroids than booids. That higher-than-expected concentration of colubroid snakes suggests that the local environment became more open and seasonally dry—and, in turn, more hospitable to these active foraging types of snakes that don't require cover to hide and ambush prey—at an earlier time in Africa than in most other parts of the world, as documented in previous studies.

"This finding gives further strength to the idea that tectonic activity in the East African Rift has helped to shape animal habitats in fascinating ways," said Nancy Stevens, an associate professor of biomedical sciences at Ohio University and co-author of the study. "The fossils suggest a fundamental shift toward more active and potentially venomous snakes that could exert very different pressures on the local fauna."

More fossils from additional locations should indicate whether colubroid snakes dominated all of Africa during the Oligocene or just the local region around the Rukwa Rift, McCartney said.

The study published in PLOS ONE describes eight different types of fossil snakes from the Rukwa Rift (five colubroid and three booid), with vertebrae ranging in length from 2.6 mm to just over 5 mm.

Citation
McCartney JA, Stevens NJ, O’Connor PM (2014) The Earliest Colubroid-Dominated Snake Fauna from Africa: Perspectives from the Late Oligocene Nsungwe Formation of Southwestern Tanzania. PLoS ONE 9(3): e90415. doi:10.1371/journal.pone.0090415


Monday, March 10, 2014

Jurassic sites link fossil communities of amphibians, reptiles, and mammals

The fossil salamander Chunerpeton shows the
preserved skeleton, the skin, and  external gills.
Photo Credit: Society of Vertebrate Paleontology.

Over the last two decades, huge numbers of fossils have been collected from the western Liaoning Province and adjacent parts of northeastern China, including exceptionally preserved feathered dinosaurs, early birds, and mammals. Most of these specimens are from the Cretaceous Period, including the famous Jehol Biota. However, in recent years many fossils have emerged from sites that are 30 million years earlier, from the Middle-Upper Jurassic Period, providing an exceptional window on life approximately 160 million years ago. A new paper published in latest issue of the Journal of Vertebrate Paleontology shows that several of these Jurassic sites are linked together by shared species and can be recognized as representing a single fossil fauna and flora, containing superbly preserved specimens of a diverse group of amphibian, mammal, and reptile species.

This fossil assemblage, newly named the Daohugou Biota after a village near one of the major localities in Inner Mongolia, China, dates from a time when many important vertebrate groups, including our own group, mammals, were undergoing evolutionary diversification. The Daohugou Biota makes an immense contribution to our understanding of vertebrate evolution during this period, with such notable creatures as the oldest known gliding mammal, another early mammal that may have swum with a beaver-like tail, the oldest dinosaurs preserved with feathers, and a pterosaur that represents an important transitional form between two major groups. As described by Dr. Corwin Sullivan, lead author of the study, "The Daohugou Biota gives us a look at a rarely glimpsed side of the Middle to Late Jurassic -- not a parade of galumphing giants, but an assemblage of quirky little creatures like feathered dinosaurs, pterosaurs with 'advanced' heads on 'primitive' bodies, and the Mesozoic equivalent of a flying squirrel."

Almost more impressive than the diversity of the biota is the preservation of many of the vertebrate specimens, including complete or nearly-complete skeletons associated with preserved soft tissues such as feathers, fur, skin or even, in some of the salamanders, external gills. Dr Yuan Wang, co-author of the study, explained, "The Daohugou amphibians are crucially important in the study of the phylogeny and early radiation of modern amphibian groups."

Dr. Paul Barrett, dinosaur researcher at the Natural History Museum, London, who was not involved with the study, commented, "Daohugou is proving to be one of the key sites for understanding the evolution of feathered dinosaurs, early mammals, and flying reptiles, due largely to the fantastic levels of preservation. Many of the fossils are stunning and offer vast amounts of information. There are only a handful of similar sites elsewhere in the world and this article represents the first comprehensive attempt to draw all of the relevant information together into a single benchmark paper." Because the Daohugou Biota and the much better studied Jehol Biota are similar in preservational mode and geographic location, but separated by tens of millions of years, they give palaeontologists an outstanding, even unique, opportunity to study changes in the fauna of this region over a significant span of geological time and an important period in vertebrate evolution. As Dr. Sullivan further remarked, "The Cretaceous feathered dinosaurs of northeastern China have been astonishing palaeontologists and the public for almost two decades now, and the Daohugou Biota preserves their Jurassic counterparts in the same region. As prequels go, it's pretty exciting."

Citation
Corwin Sullivan, Yuan Wang, David W. E. Hone, Yuanqing Wang, Xing Xu, Fucheng Zhang. The vertebrates of the Jurassic Daohugou Biota of northeastern China. Journal of Vertebrate Paleontology, 2014; 34 (2): 243 DOI: 10.1080/02724634.2013.787316

Friday, March 7, 2014

Interspecific aggression in garter snakes

The aquatic garter snake at Sibley Volcanic Regional Preserve, Oakland, CA. 
Photo credit: Sarah Stierch.
Aggressive behavior is used in many vertebrate communities to gain control of resources,  snakes, however, have been thought the exception. Some snake species use male-to-male combat for access to females, but this is intraspecies behavior.  Food partitioning usually thought to shape community structure of snake communities. A new study by Edgehouse and colleagues used two species of garter snakes at the Santa Lucia Preserve in Monterey Co. California. Both the common garter snake,Thamnophis sirtalis, the aquatic garter snake, a T. atratus and western terrestrial garter snake T. elegans coexist with their abundant, toxic prey  the California newt, Taricha torosa. At the study site,  Thamnophis sirtalis and T. atratus are aquatic and demonstrate independently evolved resistance to tetrodotoxin (TTX), a potent neurotoxin, found in the skin of the newt.

Edgehouse et al.  show that the common garter snake (Thamnophis sirtalis) and the aquatic garter snake (Thamnophis atratus) show a strong preference for amphibians and forces these snakes to exploit aquatic habitats. They investigate the aggressive behavior of T. sirtalis and the potential that this aggression displaces T. atratus from its preferred habitat. When individuals from either species were alone, they showed a complete preference for aquatic or near aquatic habitats. In contrast, when these species are together, T. sirtalis occupy the aquatic habitat and T. atratus occupy an area far removed from the water. They found Thamnophis sirtalis often physically force T. atratus from the aquatic habitat through repeated biting and other displays of aggression.

The spatial partitioning documented by the authors is likely a direct result of food availability and aggressive defense of the prey resource. The most abundant amphibian prey found in the snakes at the study site were California newt and the pacific treefrog.

Citation
Edgehouse M, Latta LC IV, Brodie ED III, Brodie ED Jr (2014) Interspecific Aggression and Habitat Partitioning in Garter Snakes. PLoS ONE 9(1): e86208. doi:10.1371/journal.pone.0086208

Sunday, March 2, 2014

Herpetofauna of the the Tay Yen Tu Nature Reserve, Vietnam

Rhynchophis boulengeri , one of the colubrids present at Tay Yen Tu. JCM

The Tay Yen Tu Nature Reserve is located in Bac Giang Province, about 100 km northeast of Hanoi, Vietnam and is situated in the western side of theYen Tu massif, which is the largest granitic formation in northeastern Vietnam. The main habitat of the area is evergreen broad-leaved tropical forest. The total area of the reserve is 16 ha and includes two non-contiguous sectors: the Thanh Son-Luc Son sector and the Khe Ro sector. The Thanh Son-Luc Son sector is centered on the 1,068 m high Mount Yen Tu, while the Khe Ro sector is about 886 m on Mount Da Bac. A comprehensive study on the biodiversity has not been conducted in the reserve to date, However, preliminary field research indicates the area supports a number of species of national or global conservation concern. Four new species have been discovered from Yen Tu Mountain in the last decade: Sphenomorphus cryptotis, Scincella devorator, Tylototriton vietnamensis and Odorrana yentuensis. Additionally, three new country records were recently reported from this nature reserve: Shinisaurus crocodilurus, Amphiesmoides ornaticepsm, and Rhacophorus maximus.  The discoveries of new reptiles and amphibians from Yen Tu Mountains underscore the unrealized biodiversity of northeastern Vietnam. Based on the results of recent field surveys Hetch et al. (2014) provide the first list of amphibians and reptiles recorded from Tay Yen Tu Nature Reserve.

A total of 76 species of amphibians and reptiles were recorded, including one caecilian, one newt, 34 species of anurans, 18 species of lizards, and 22 species of snakes. Thirty species are reported for the first time. Among the recorded species, five are currently known only from Vietnam. A high level of species diversity and endemism of the herpetofauna underscores the importance of biodiversity conservation in this nature reserve, which covers a major part of the remaining lowland evergreen forest in northeastern Vietnam.

Citation
Hecht, Vera L., Cuong T. Pham, Tao T. Nguyen, Truong Q. Nguyen, Michael Bonkowski, and Thomas Ziegler.  2014. First report on the herpetofauna of Tay Yen Tu Nature Reserve, northeastern Vietnam. Biodiversity Journal, 4 (4): 507–552.

Risk assessment for Burmese pythons in Everglades National Park

A large Burmese python, weighing 162 pounds and more than 15 feet 
long at the time of its capture in 2009. Caught alive in the Everglades, 
it had eaten an American alligator that measured about 6 feet in 
length. University of Florida researchers in the photo: Michael 
Rochford is holding the python's head, and Alex Wolf and Therese 
Walters are holding the python's body. Photo credit USGS.
The estimated tens of thousands of Burmese pythons now populating the Everglades present a low risk to people in the park, according to a new assessment by U.S. Geological Survey and National Park Service scientists.

The human risk assessment looked at five incidents that involved humans and Burmese pythons over a 10-year period in Everglades National Park. All five incidents involved pythons striking at biologists who were conducting research in flooded wetlands.

"Visitor and staff safety is always our highest priority at Everglades National Park," said Superintendent Dan Kimball. "Everglades, as many other national parks, draws many thousands of visitors for the opportunity to view the wildlife that live here in a natural setting. Our guidance to visitors with respect to Burmese pythons is the same as for our native wildlife -- please maintain a safe distance and don't harass the wildlife. With respect to controlling Burmese pythons, we are working diligently with our state, federal, tribal, and local partners to manage this invasive species and educate the public on the importance of not letting invasive species loose in the wild."

Although there have been numerous bites to people provoking Burmese pythons by attempting to capture or kill the snakes, this study examined only unprovoked strikes directed at people.

"The strikes did not appear to be defensive, but were more likely were associated with aborted feeding behavior," said USGS wildlife biologist and herpetologist Bob Reed, the lead author of the study. "Pythons usually direct defensive strikes at the front of a person, not from the side or rear, as all of these strikes were. Additionally, Burmese pythons rely on being secretive and evading detection as their primary means of avoiding interactions with people, and typically don't strike until provoked."

The biologists did not detect any of the snakes before the strikes occurred, making it even more likely that the attacks were related to feeding and not defense, Reed noted. Two of the attacks resulted in very minor injuries from the pythons' teeth and none involved constriction.

Reed and his co-author, retired Everglades National Park scientist Skip Snow, consider the attacks as cases of mistaken identity. In four of five cases the python was small compared to the size of the person, which resulted in the snake likely aborting the attack upon realizing the large size of its prey. Aborting strikes before actual bites with the possible prey indicates that pythons may be able to assess the size of the prey mid-strike and adjust accordingly, the study said.

Although the pythons' threat to people is low, previous studies have shown that this invasive snake species is having a negative effect on many of the native mammals in the South Florida Everglades. One study suggests the population of raccoons, opossums, and bobcats have declined significantly in the regions of Everglades National Park where pythons have been established the longest.

More than one million people visit Everglades National Park every year, often traveling along hiking and canoeing trails where Burmese pythons have been spotted or captured. Despite this close interaction, the study noted that none of the reported incidents involved a park visitor. All of the incidents were directed at biologists moving through remote and flooded areas of the park.

"As people wade through shallow water, they produce ripples that move ahead of them, and these pressure waves may be detectable to a motionless snake in ambush posture," said Reed. "We speculate that detecting these changes in water pressure may alert a python that an animal is approaching, perhaps priming it to strike immediately when a potential prey item is detected."

Burmese pythons became established in Florida several decades ago as a result of the international pet trade. The largest snakes removed from the Everglades have exceeded 18 feet and 150 pounds. Snakes of this size are capable of ingesting large prey like deer and alligators.

This human risk assessment concluded that although the risk of an unprovoked attack by a Burmese python in Everglades National Park is low, it is not non-existent. Available evidence from captive snakes suggests that even those strikes that result from cases of mistaken identity or defensive behavior may still result in constriction, which can prove fatal to people when a large python or a small human is involved.

The study focused only on the risk associated with Burmese pythons, but did not address other invasive constrictor species, such as the Northern African python, which is also known as the African Rock python, which are also known to be established and breeding in South Florida outside of Everglades National Park. USGS scientists continue to work with partners to better understand the impacts on invasive reptiles in the Everglades, help reduce their spread into new areas and help prevent new species from becoming established.

Citation
RN Reed, RW Snow. 2014 Assessing risks to humans from invasive Burmese pythons in Everglades National Park, Florida, USA. Wildlife Society Bulletin, DOI: 10.1002/wsb.413